Mercury – Fuel Line Assembly | Fuel System | Gray Low-Permeation Hose | 8M0078628

Overview

Every boater has their little pre-launch rhythm, and the primer bulb squeeze is usually part of it. When it firms up smoothly beneath your hand, there’s a sense of calm that settles in — a quiet confirmation that the fuel system is doing exactly what it should. The Mercury Fuel Line Assembly 8M0078628 is built around that simple, reassuring moment. Whether you’re easing into a morning drift or running home through afternoon chop, this assembly keeps fuel moving clean, steady, and dependable so you can focus on the water instead of the gear behind you.

Key Features

• Five-sixteenth-inch inside diameter hose provides consistent, reliable fuel flow
• Low-permeation construction helps preserve fuel quality and minimize fumes.
• Mercury-engineered primer bulb delivers firm, predictable priming pressure.
• Gray heat-reflective exterior helps reduce vapor-lock risk
• Flexible marine-grade hose designed for long-term exposure and durability.
• Compatible with multiple tank and engine connector configurations
• Ideal for portable tanks, built-in systems, and custom rigging setups

Engine & Boat Compatibility

• Fits Mercury and Mariner outboards using universal five-sixteenth-inch fuel lines
• Suitable for small to mid-range horsepower engines across many model years
• Great for pontoons, runabouts, aluminum fishing boats, skiffs, tenders, and inflatables
• Adapts easily to various portable and fixed tank types with the correct fittings

Performance & Practical Benefits

You can feel the quality immediately. The primer bulb builds pressure smoothly and confidently, giving you that clear sense that the fuel is flowing exactly the way it should. The hose routes naturally through tight rigging spaces, flexing smoothly around corners without kinking or collapsing — a detail that becomes especially important when the boat hits chop or shifts weight.

On hot, sunny days, the gray exterior helps reflect heat instead of absorbing it, keeping the fuel line cooler and reducing vapor-lock risk during longer runs. The low-permeation hose also cuts down on gasoline smell and slows evaporation, which makes a meaningful difference when your boat spends time under a cover or stored indoors. Over time, the hose stays flexible rather than becoming brittle, and the primer bulb maintains its firm, responsive feel season after season. The result is easier starts, smoother idle, and fewer fuel-related issues throughout your boating season.

Why Buy OEM

Genuine Mercury Marine parts simply deliver the reliability boaters depend on. Every component — from the hose blend to the internal valves of the primer bulb — is engineered specifically for the demands of marine use. Aftermarket assemblies may look similar, but they rarely match the priming strength, durability, or long-term consistency of Mercury’s design. Choosing OEM means proper fit, predictable performance, and the confidence that your fuel system will behave exactly the way it should when you’re out on the water. It’s the practical, no-nonsense choice for anyone who values trouble-free boating.

FAQ.

Q1: Which engines does the 8M0078628 Fuel Line Assembly fit?

It fits Mercury and Mariner outboards using a universal five-sixteenth-inch fuel line, once matched with the proper connectors for your tank and engine.

Q2: How is this different from aftermarket assemblies?

Mercury’s engineering provides stronger priming, better long-term hose flexibility, and more reliable fuel delivery overall.

Q3: How do I confirm this is the right replacement?

Check your current hose diameter and connector styles. If your system uses a five-sixteenth-inch line, this assembly typically fits once paired with the correct fittings.

Q4: Can it be used in both saltwater and freshwater?

Yes. It’s designed for dependable performance in either environment.

Q5: Is installation straightforward?

Very. Install the correct connectors, route and secure the hose neatly, and most boaters can complete the job without difficulty.